Good Question.
In my games...
Several of my parties have faced the racially mixed forces. The Dragon doesn't care what his military make up is. As long as they work. Punishments are harsh. People that live in the area of course know the structure. As you move farther away the military makeup becomes just that, a distant face that they don't recognize. Eventually they become "those soldiers over there". The makeup assumed to be all human. There will always be exceptions, like merchants, rangers, raiders and the like. They will have first hand vision of things military.
He is simply called "The Dragon", reverence is expected. Most have no clue what a Dragon Lord is. Although Dragon sightings in that area are higher then usual. There are the elite that know, The Dragon's personal servants and guards. Those that live and serve in his Keep may suspect, but fear the truth or many simply don't understand what they are looking at. I always played it that there were few that "Deserved to Know". I am a firm believer that Knowledge is Power. The Dragon does not willingly share power.
The only people that know about the battles, are those that have been there, people that talk to merchants (that have been there), or People with an interest in the area, for example: spy's, thieves, speciality groups, seers and wise women that just seem to know the most peculiar things, Royals, trusted nobles (or those with an interest in the area in question) and the occasional adventurer. In every game I run with a "Free Radical", a person that heard/experienced/saw something they shouldn't have. They tend to be my hooks to pull players in certain directions, in case my party is extra thick that day.
That is about as far as I have gone with that region.